The overall goal of Project 5 will be characterize the functional role of subcortical loops through the basal ganglia and through the cerebellum in the integration of motor programs across time. We will use a dual-chamber recording technique to study pairs of neurons, one in a targeted area of the frontal cortex and the other in the globus pallidus or in the cerebellar nucleus. A cortical and a subcortical neuron pair will be selected based on the likelihood that the subcortical neuron sends synaptic input, via thalamus, to the cortical neuron. In this manner, single units at the pair of sites can be studied simultaneously, while a monkey performs a task that integrates motor programs across time. The three tasks that we will study are designed are designed to parallel the tasks being studied in other projects of this PPG, so that we can profit optimally from the close interactions promoted by this comprehensive program of motor systems research. To interface with Project 2, we will study the on-line correction of errors that result from small perturbations introduced while the task is being performed. To interface with Project 3, we will study the execution of skilled movement sequences that have been learned through extended periods of practice. To interface with Project 4, we will study the sequential movements made when copying geometrical figures. We will use both paired-site single unit recordings and microinjection of antagonists to inactivate the subcortical site. In this manner, we will investigate how output signals from single neurons located in identified channels passing through the basal ganglia and through the cerebellum function to regulate the signals that are simultaneously recorded from a cortical neuron.